Due to the growing demand for energy throughout the world, concerns have grown about the future of the world's energy supplies. Not only are there limited supplies of oil and coal reserves available within the earth's crust, but due to the ongoing security problems and concerns that now exist throughout the world today, there has been a growing desire to reduce our nation's reliance on foreign oil.
Indeed, many energy experts believe that a successful energy solution must include the ability to harness energy from what are often called natural renewable resources, such as the sun and wind. The renewability and abundant availability of these resources make them well suited to the development of potentially viable long term solutions, and many believe that whatever efforts that are currently being made to use these resources must significantly be expanded before the world's oil and coal reserves eventually run out.
One problem associated with the use of renewable energy such as the sun and wind is that the energy is not always available when the energy is needed. Solar power, for example, is only available during the day, and is most effective when the sun is shining brightly, and therefore, the extent to which energy can be provided by the sun is not always predictable. Wind energy is also only available when the wind is blowing, and therefore, it is not a highly reliable source of energy. Another drawback to these resources is that even when energy is available, the amount of energy that they generate is not always consistent. For example, even when the wind blows, it does not always blow at the same speed, or at regular intervals, and therefore, the amount of energy that can be generated is not always consistent. The same is true of solar energy, i.e., the degree to which the sun is shining and available can be sporadic; it often depends on the weather, and therefore, it is never certain how much energy can be generated at any given moment in time.
One potential solution to these problems is to store the energy during times when the energy is available, and using the energy when it is needed most. This is often referred to as time-shifting. Nevertheless, one problem associated with time-shifting relates to the inherent inefficiencies that can result from having to store energy in one form, and then converting the energy into another form before it can be used. This is especially true of compressed air energy storage systems that store compressed air in high pressure storage tanks, wherein the energy must be converted by a generator to produce usable electricity. In such case, the energy used from storage can often end up costing more than the energy that was stored. These inefficiencies can significantly reduce the economic incentives that are needed to promote the installation of these potentially viable systems.
Notwithstanding these problems, because the sun represents a significant natural resource that will never run out, there is a strong desire to develop a system that can not only harness the sun's energy, i.e., to produce electricity, but to store the energy, and do so in a manner that is efficient and cost-effective, wherein the energy that is generated can then be made available on a continuous and uninterrupted basis, so that it can be used during peak demand periods, as well as when little or no sun is available. Moreover, while there has been a steady increase in the number of photovoltaic (PV) cell projects that have been initiated and developed in recent years, each of these projects has had a serious shortfall in electric power production particularly in the late afternoon and early evening when the power demand is high. Thus there is a need to install a PV panel system wherein the excess energy can be collected and stored during the high solar irradiation period and then used during the weaker solar irradiation period.